Re: [boost] [smart_ptr] Is there any interest in unique_ptr with type erased deleter?

21 Mar 2017


      On Tue, Mar 21, 2017 at 11:10 AM, TONGARI J via Boost 
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2017-03-21 15:04 GMT+08:00 Andrey Davydov via Boost 
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I have implemented smart pointer with semantics of unique ownership and
type erased deleter (https://github.com/AndreyG/unnamed). It has size
of 3
pointers and it doesn't require additional memory allocations for the
case
when deleter is empty class (for example, std::default_delete or
non-capturing lambda) and for the case when deleter is known at compile
time function (for instance, fclose). The are some simple examples of
usage
and tests in the repo.
Why don't just use unique_ptr>? The main reason
is that due to the small object optimization std::function has rather big
size. For instance, sizeof(unique_ptr>) == 72
for
MSVC x64! Results for the other platforms can be found in the repo
README.
Does it seem useful?
Why not:
```
template<class T>
using my_ptr = unique_ptr;
```
? Even if you need a stateful deleter, you don't need to reinvent the whole
unique_ptr, just use your custom type-erased deleter.
Because I'd like, for example, cast my_ptr<Derived> to my_ptr<Base>.

-- 
Andrey Davydov